rotary.enthusiast

Horsepower and torque are both crap if you just throw them out as a single peak number like most people do. "My car makes 350 HP!!!" Big deal. The only way to evaluate an engine's performance in a meaningful way is to look at an entire dyno plot... and in that case, either HP or torque would do (you can derive one from the other after all).

That being said, I'd much rather look at a torque curve than a HP curve.

MazdaManiac

iTrader: (3)

Torque is as close to a "raw" number as you can get.
Horsepower is a calculation, so you have to start thinking about time and gearing and it just doesn't do anything for you when you are looking for optimal fuel and timing.

Tune for torque, get it right and then turn on the CF to SAE and hand the owner a horsepower plot to make them happy.
(j/k)

rotary.enthusiast

That's pretty much how it goes

I agree that you generally want to increase torque everywhere when possible, but if you can gain high end torque by sacrificing low end torque (say be fiddling with the intake runner length or something) then it could be worth it depending on where the engine's output currently is, how the transmission is geared, and what you plan on doing with the car.

Anyway, I'm not really disagreeing with you, I'm just bored and upping my post count. I'll shut up now

MazdaManiac

iTrader: (3)

^^ You are spot-on, so jack that post count!

Brettus

iTrader: (2)

a flat torque curve is nice but not that much good to you on a road course - my revs never drop below 5500 so tell me how having gobs of torque at 3000 is going to help me ?

MazdaManiac

iTrader: (3)

Higher gear.
One of the beautiful things about having all that torque down low is that I don't shift much on a road course.
Places where you would normally go down to 2nd are much faster for me in 3rd.
I can do most of Firebird west entirely in 3rd.
Its only in the straights I need to shift because I'm getting into triple-digits.

Brettus

iTrader: (2)

So really what you are saying is that having more torque low down makes the car easier to drive fast due to fewer gear changes . That is a fair point and i guess it would help most drivers .
For good drivers I doubt it would make that much difference - it just means it takes more effort and skill to keep the engine in the optimum rev range .

pdxhak

iTrader: (2)

tighter courses and shifting less generally means you should be faster. this of course assumes all things being equal.

MazdaManiac

iTrader: (3)

Good or not, any time spent in between gears is time not doing something fast.
Also, at higher revs (engine wear not withstanding), the effects of lift-throttle are totally different.

Brettus

iTrader: (2)

so what is the lowest revs you would drop to on he track , with your setup ?

MazdaManiac

iTrader: (3)

3k or so, I guess. If I had to go below that, I'd down-shift.
IDK. I've never really thought about it.
I just drive and mash it.

Brettus

iTrader: (2)

I think if you paid attention you would find it is a lot higher than you guessed
Even with your setup - if you were going below 4500 i would have to say your driving sucks .......

maxxdamigz

iTrader: (1)

Well, I'm pretty sure if you came out of a turn in third that another similar Rx-8 downshifted to second, he would blow your doors off traction not withstanding. If you're at 3000 rpms, he's at about 4200. Not only is he closer to his torque peak, but he is also taking advantage of a 35-40% mechanical advantage from being in a lower gear. I'm not a competitive racer, but that's simple math.

Now, I'm not going to get into the tune for torque circle jerk. Any car you're tuning has a fixed functional RPM range, and, thus, a fixed multiplier for HP. Tuning for the most torque will get you the most hp. Tuning for the broadest torque as well will get you the broadest power curve. That's just proper tuning. However, when driving, you have to be mindful of where your car makes it's maximum power as that is the best combination of torque and gearing that you will get. If you had a gear box set up so that at 40 miles an hour, 3rd put you at your torque peak and 2nd put you at your horsepower peak, driving in second would put more torque to the ground.

Conversely, if your car is all top end, you can actually be a fairly poor drag car. I often hear this as Supra Syndrome. You either have to spin the crap out of the wheels to avoid bogging in your low rpms or you lose more time getting out of first than your top end can make up.

Then again, all this is resultant of getting a good tune on the parts you put in your car. So friends don't let friends drive on bad tunes?

MazdaManiac

iTrader: (3)

Like I said, IDK.
I do know that in third, coming around just about any corner at any speed, I have to be mindful of the throttle or it will light up.

invasion08

iTrader: (7)

Keep in mind that the MAZSPORT TURBO KIT was not pushed harder since the owner of the car did not want to go any higher. I am sure Scott could have gotten a few hp if the owner allowed him too.

mysql

What the hell does that mean?

It's already at 13 psi. Why didn't you put a disclaimer that the Pettit kit didn't do 16 psi because the owner didn't want to push it higher?

The BHR kit is still running 9 psi. You sure as hell can go higher with it, as can any other kit listed (besides the stock greddy kit, since that's pretty much as high as it can go)

invasion08

iTrader: (7)

It means i believe that Mazsport could have gotten more rwhp if the owner would have let them. I do not know if the owner only wanted to go to 13psi.

MazdaManiac

iTrader: (3)

That's not really how tuning works.

ChrisRX8PR

iTrader: (1)

That is sweet! With my current tune, which has changed a bit since we did the dyno, the car lights up the tires in third when it goes over 6000 in the dry going straight down the highway. And that is with 19X10 and 275 sticky rubber in the rear. Lots of fun but at times it gets scary. You must be enjoying your car incredibly. Above 350whp is where they really start getting fun.

Chris

05rex8

iTrader: (7)

shoot, I would be happy with 300rwhp....

again, nice job guys

suay

My dcs is going off also and the switch/button doesn't dp anything when pressed. I afraid it will suddenly come on when I take it for autoXing soon. ouch!
My tuning is coming in the 20th of sept. maybe the tuning guy will answer my questions. Anyone know why?


mazsport stage 1 kit plus ignition solution

05rex8

iTrader: (7)

^check to see if your flashes are recent with mazda like swoope said

636

Well , time to start saving money for a turbo kit lol . Why do you guys like to empty my bank so much? You guys are evil , that money could have gone to my heart transplant , but no. Good job on the kit , any idea on reliability? Is running 13 psi "pushing the limit"?

suay

This is what i was told from scott kit and he said "every so often". He was relaying to the 400 hp you all die to have. I haven't tuned mine yet but F it I will do the deed! Good job on the readings and may the boost be with you!

MazdaManiac

iTrader: (3)

Already been done.
The problem is it is problematic in a hot environment on street fuel.

I wouldn't drive my car every day like that, so the dyno is meaningless to me.